[PATCH 3/6] can: mcp25xxfd: Add support for CAN reception

[Manivannan Sadhasivam]

From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>

Add un-optimized CAN2.0 and CAN-FD reception support.

On a Rasperry pi 3 it is already able to process CAN2.0 Frames
with DLC=0 on a CAN bus with 1MHz without losing any packets
on the SPI side. Packets still get lost inside the network stack.

Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
[mani: misc cleanups for upstream]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
---
 drivers/net/can/spi/mcp25xxfd/Makefile        |   3 +
 .../net/can/spi/mcp25xxfd/mcp25xxfd_base.c    |   6 +
 drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can.c | 395 ++++++++++-
 drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can.h |  35 +
 .../can/spi/mcp25xxfd/mcp25xxfd_can_fifo.c    | 228 ++++++
 .../can/spi/mcp25xxfd/mcp25xxfd_can_fifo.h    |  16 +
 .../net/can/spi/mcp25xxfd/mcp25xxfd_can_id.h  |  69 ++
 .../net/can/spi/mcp25xxfd/mcp25xxfd_can_int.c | 655 ++++++++++++++++++
 .../net/can/spi/mcp25xxfd/mcp25xxfd_can_int.h |  18 +
 .../can/spi/mcp25xxfd/mcp25xxfd_can_priv.h    | 131 ++++
 .../net/can/spi/mcp25xxfd/mcp25xxfd_can_rx.c  | 233 +++++++
 .../net/can/spi/mcp25xxfd/mcp25xxfd_can_rx.h  |  18 +
 drivers/net/can/spi/mcp25xxfd/mcp25xxfd_int.c |  14 +-
 .../net/can/spi/mcp25xxfd/mcp25xxfd_priv.h    |   2 +
 .../net/can/spi/mcp25xxfd/mcp25xxfd_regs.h    |   5 +
 15 files changed, 1823 insertions(+), 5 deletions(-)
 create mode 100644 drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_fifo.c
 create mode 100644 drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_fifo.h
 create mode 100644 drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_id.h
 create mode 100644 drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_int.c
 create mode 100644 drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_int.h
 create mode 100644 drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_priv.h
 create mode 100644 drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_rx.c
 create mode 100644 drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_rx.h

diff --git a/drivers/net/can/spi/mcp25xxfd/Makefile b/drivers/net/can/spi/mcp25xxfd/Makefile
index d8fdb76a9578..5787bdd57a9d 100644
--- a/drivers/net/can/spi/mcp25xxfd/Makefile
+++ b/drivers/net/can/spi/mcp25xxfd/Makefile
@@ -1,6 +1,9 @@
 obj-$(CONFIG_CAN_MCP25XXFD)	+= mcp25xxfd.o
 mcp25xxfd-objs                  := mcp25xxfd_base.o
 mcp25xxfd-objs                  += mcp25xxfd_can.o
+mcp25xxfd-objs                  += mcp25xxfd_can_fifo.o
+mcp25xxfd-objs                  += mcp25xxfd_can_int.o
+mcp25xxfd-objs                  += mcp25xxfd_can_rx.o
 mcp25xxfd-objs                  += mcp25xxfd_cmd.o
 mcp25xxfd-objs                  += mcp25xxfd_crc.o
 mcp25xxfd-objs                  += mcp25xxfd_ecc.o
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_base.c b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_base.c
index 4be456df0998..c6b67c54a3cd 100644
--- a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_base.c
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_base.c
@@ -123,6 +123,11 @@ static int mcp25xxfd_base_probe(struct spi_device *spi)
 	if (ret)
 		goto out_power;
 
+	/* setting up CAN */
+	ret = mcp25xxfd_can_setup(priv);
+	if (ret)
+		goto out_power;
+
 	dev_info(&spi->dev,
 		 "MCP%04x successfully initialized.\n", model);
 	return 0;
@@ -140,6 +145,7 @@ static int mcp25xxfd_base_remove(struct spi_device *spi)
 {
 	struct mcp25xxfd_priv *priv = spi_get_drvdata(spi);
 
+	mcp25xxfd_can_remove(priv);
 	mcp25xxfd_base_power_enable(priv->power, 0);
 	clk_disable_unprepare(priv->clk);
 
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can.c b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can.c
index 41a5ab508582..2ac78024c171 100644
--- a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can.c
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can.c
@@ -5,15 +5,119 @@
  * Copyright 2019 Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
  */
 
+#include <linux/bitfield.h>
+#include <linux/can/core.h>
+#include <linux/can/dev.h>
 #include <linux/device.h>
+#include <linux/interrupt.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
 #include <linux/spi/spi.h>
 
+#include "mcp25xxfd_base.h"
+#include "mcp25xxfd_can_fifo.h"
+#include "mcp25xxfd_can_int.h"
+#include "mcp25xxfd_can_priv.h"
 #include "mcp25xxfd_can.h"
 #include "mcp25xxfd_cmd.h"
+#include "mcp25xxfd_int.h"
 #include "mcp25xxfd_priv.h"
 #include "mcp25xxfd_regs.h"
 
+#include <uapi/linux/can/netlink.h>
+
+/* everything related to bit timing */
+static
+const struct can_bittiming_const mcp25xxfd_can_nominal_bittiming_const = {
+	.name           = DEVICE_NAME,
+	.tseg1_min      = 2,
+	.tseg1_max      = BIT(MCP25XXFD_CAN_NBTCFG_TSEG1_BITS),
+	.tseg2_min      = 1,
+	.tseg2_max      = BIT(MCP25XXFD_CAN_NBTCFG_TSEG2_BITS),
+	.sjw_max        = BIT(MCP25XXFD_CAN_NBTCFG_SJW_BITS),
+	.brp_min        = 1,
+	.brp_max        = BIT(MCP25XXFD_CAN_NBTCFG_BRP_BITS),
+	.brp_inc        = 1,
+};
+
+static
+const struct can_bittiming_const mcp25xxfd_can_data_bittiming_const = {
+	.name           = DEVICE_NAME,
+	.tseg1_min      = 1,
+	.tseg1_max      = BIT(MCP25XXFD_CAN_DBTCFG_TSEG1_BITS),
+	.tseg2_min      = 1,
+	.tseg2_max      = BIT(MCP25XXFD_CAN_DBTCFG_TSEG2_BITS),
+	.sjw_max        = BIT(MCP25XXFD_CAN_DBTCFG_SJW_BITS),
+	.brp_min        = 1,
+	.brp_max        = BIT(MCP25XXFD_CAN_DBTCFG_BRP_BITS),
+	.brp_inc        = 1,
+};
+
+static int mcp25xxfd_can_do_set_nominal_bittiming(struct net_device *net)
+{
+	struct mcp25xxfd_can_priv *cpriv = netdev_priv(net);
+	struct can_bittiming *bt = &cpriv->can.bittiming;
+	int sjw = bt->sjw;
+	int pseg2 = bt->phase_seg2;
+	int pseg1 = bt->phase_seg1;
+	int propseg = bt->prop_seg;
+	int brp = bt->brp;
+	int tseg1 = propseg + pseg1;
+	int tseg2 = pseg2;
+
+	/* calculate nominal bit timing */
+	cpriv->regs.nbtcfg = ((sjw - 1) << MCP25XXFD_CAN_NBTCFG_SJW_SHIFT) |
+		((tseg2 - 1) << MCP25XXFD_CAN_NBTCFG_TSEG2_SHIFT) |
+		((tseg1 - 1) << MCP25XXFD_CAN_NBTCFG_TSEG1_SHIFT) |
+		((brp - 1) << MCP25XXFD_CAN_NBTCFG_BRP_SHIFT);
+
+	return mcp25xxfd_cmd_write(cpriv->priv->spi, MCP25XXFD_CAN_NBTCFG,
+				   cpriv->regs.nbtcfg);
+}
+
+static int mcp25xxfd_can_do_set_data_bittiming(struct net_device *net)
+{
+	struct mcp25xxfd_can_priv *cpriv = netdev_priv(net);
+	struct mcp25xxfd_priv *priv = cpriv->priv;
+	struct can_bittiming *bt = &cpriv->can.data_bittiming;
+	struct spi_device *spi = priv->spi;
+	int sjw = bt->sjw;
+	int pseg2 = bt->phase_seg2;
+	int pseg1 = bt->phase_seg1;
+	int propseg = bt->prop_seg;
+	int brp = bt->brp;
+	int tseg1 = propseg + pseg1;
+	int tseg2 = pseg2;
+	int tdco;
+	int ret;
+
+	/* set up Transmitter delay compensation */
+	cpriv->regs.tdc = FIELD_PREP(MCP25XXFD_CAN_TDC_TDCMOD_MASK,
+				     MCP25XXFD_CAN_TDC_TDCMOD_AUTO);
+
+	/* configure TDC offsets */
+	tdco = clamp_t(int, bt->brp * tseg1, -64, 63);
+	cpriv->regs.tdc &= ~MCP25XXFD_CAN_TDC_TDCO_MASK;
+	cpriv->regs.tdc |= FIELD_PREP(MCP25XXFD_CAN_TDC_TDCO_MASK, tdco);
+
+	/* set TDC */
+	ret = mcp25xxfd_cmd_write(spi, MCP25XXFD_CAN_TDC, cpriv->regs.tdc);
+	if (ret)
+		return ret;
+
+	/* calculate data bit timing */
+	cpriv->regs.dbtcfg =
+		FIELD_PREP(MCP25XXFD_CAN_DBTCFG_SJW_MASK, (sjw - 1)) |
+		FIELD_PREP(MCP25XXFD_CAN_DBTCFG_TSEG2_MASK, (tseg2 - 1)) |
+		FIELD_PREP(MCP25XXFD_CAN_DBTCFG_TSEG1_MASK, (tseg1 - 1)) |
+		FIELD_PREP(MCP25XXFD_CAN_DBTCFG_BRP_MASK, (brp - 1));
+
+	return mcp25xxfd_cmd_write(spi, MCP25XXFD_CAN_DBTCFG,
+				   cpriv->regs.dbtcfg);
+}
+
 int mcp25xxfd_can_get_mode(struct mcp25xxfd_priv *priv, u32 *reg)
 {
 	int ret;
@@ -25,10 +129,10 @@ int mcp25xxfd_can_get_mode(struct mcp25xxfd_priv *priv, u32 *reg)
 	return FIELD_GET(MCP25XXFD_CAN_CON_OPMOD_MASK, *reg);
 }
 
-static int mcp25xxfd_can_switch_mode(struct mcp25xxfd_priv *priv,
-				     u32 *reg, int mode)
+int mcp25xxfd_can_switch_mode_no_wait(struct mcp25xxfd_priv *priv,
+				      u32 *reg, int mode)
 {
-	int ret, i;
+	int ret;
 
 	ret = mcp25xxfd_can_get_mode(priv, reg);
 	if (ret < 0)
@@ -41,7 +145,15 @@ static int mcp25xxfd_can_switch_mode(struct mcp25xxfd_priv *priv,
 		FIELD_PREP(MCP25XXFD_CAN_CON_OPMOD_MASK, mode);
 
 	/* Request the mode switch */
-	ret = mcp25xxfd_cmd_write(priv->spi, MCP25XXFD_CAN_CON, *reg);
+	return mcp25xxfd_cmd_write(priv->spi, MCP25XXFD_CAN_CON, *reg);
+}
+
+int mcp25xxfd_can_switch_mode(struct mcp25xxfd_priv *priv, u32 *reg, int mode)
+{
+	int ret, i;
+
+	/* trigger the mode switch itself */
+	ret = mcp25xxfd_can_switch_mode_no_wait(priv, reg, mode);
 	if (ret)
 		return ret;
 
@@ -139,3 +251,278 @@ int mcp25xxfd_can_probe(struct mcp25xxfd_priv *priv)
 	/* Finally check if modeswitch is really working */
 	return mcp25xxfd_can_probe_modeswitch(priv);
 }
+
+static int mcp25xxfd_can_config(struct net_device *net)
+{
+	struct mcp25xxfd_can_priv *cpriv = netdev_priv(net);
+	struct mcp25xxfd_priv *priv = cpriv->priv;
+	struct spi_device *spi = priv->spi;
+	int ret;
+
+	/* setup value of con_register */
+	cpriv->regs.con = MCP25XXFD_CAN_CON_STEF; /* enable TEF, disable TXQ */
+
+	/* non iso FD mode */
+	if (!(cpriv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO))
+		cpriv->regs.con |= MCP25XXFD_CAN_CON_ISOCRCEN;
+
+	/* one shot */
+	if (cpriv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
+		cpriv->regs.con |= MCP25XXFD_CAN_CON_RTXAT;
+
+	/* apply it now together with a mode switch */
+	ret = mcp25xxfd_can_switch_mode(cpriv->priv, &cpriv->regs.con,
+					MCP25XXFD_CAN_CON_MODE_CONFIG);
+	if (ret)
+		return 0;
+
+	/* time stamp control register - 1ns resolution */
+	cpriv->regs.tscon = 0;
+	ret = mcp25xxfd_cmd_write(spi, MCP25XXFD_CAN_TBC, 0);
+	if (ret)
+		return ret;
+
+	cpriv->regs.tscon = MCP25XXFD_CAN_TSCON_TBCEN |
+			    FIELD_PREP(MCP25XXFD_CAN_TSCON_TBCPRE_MASK,
+				       ((cpriv->can.clock.freq / 1000000)));
+	ret = mcp25xxfd_cmd_write(spi, MCP25XXFD_CAN_TSCON, cpriv->regs.tscon);
+	if (ret)
+		return ret;
+
+	/* setup fifos */
+	ret = mcp25xxfd_can_fifo_setup(cpriv);
+	if (ret)
+		return ret;
+
+	/* setup can bittiming now - the do_set_bittiming methods
+	 * are not used as they get called before open
+	 */
+	ret = mcp25xxfd_can_do_set_nominal_bittiming(net);
+	if (ret)
+		return ret;
+
+	ret = mcp25xxfd_can_do_set_data_bittiming(net);
+	if (ret)
+		return ret;
+
+	return ret;
+}
+
+/* mode setting */
+static int mcp25xxfd_can_do_set_mode(struct net_device *net,
+				     enum can_mode mode)
+{
+	switch (mode) {
+	case CAN_MODE_START:
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+/* binary error counters */
+static int mcp25xxfd_can_get_berr_counter(const struct net_device *net,
+					  struct can_berr_counter *bec)
+{
+	struct mcp25xxfd_can_priv *cpriv = netdev_priv(net);
+
+	bec->txerr = FIELD_PREP(MCP25XXFD_CAN_TREC_TEC_MASK,
+				cpriv->status.trec);
+	bec->rxerr = FIELD_PREP(MCP25XXFD_CAN_TREC_REC_MASK,
+				cpriv->status.trec);
+
+	return 0;
+}
+
+static int mcp25xxfd_can_open(struct net_device *net)
+{
+	struct mcp25xxfd_can_priv *cpriv = netdev_priv(net);
+	struct spi_device *spi = cpriv->priv->spi;
+	int ret, mode;
+
+	ret = open_candev(net);
+	if (ret) {
+		netdev_err(net, "unable to set initial baudrate!\n");
+		return ret;
+	}
+
+	/* request an IRQ but keep disabled for now */
+	ret = request_threaded_irq(spi->irq, NULL,
+				   mcp25xxfd_can_int,
+				   IRQF_ONESHOT | IRQF_TRIGGER_LOW,
+				   cpriv->priv->device_name, cpriv);
+	if (ret) {
+		dev_err(&spi->dev, "failed to acquire irq %d - %i\n",
+			spi->irq, ret);
+		goto out_candev;
+	}
+
+	disable_irq(spi->irq);
+	cpriv->irq.allocated = true;
+	cpriv->irq.enabled = false;
+
+	/* enable power to the transceiver */
+	ret = mcp25xxfd_base_power_enable(cpriv->transceiver, 1);
+	if (ret)
+		goto out_irq;
+
+	/* configure controller for reception */
+	ret = mcp25xxfd_can_config(net);
+	if (ret)
+		goto out_power;
+
+	/* setting up state */
+	cpriv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+	/* enable interrupts */
+	ret = mcp25xxfd_int_enable(cpriv->priv, true);
+	if (ret)
+		goto out_canconfig;
+
+	if (cpriv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
+		mode = MCP25XXFD_CAN_CON_MODE_EXT_LOOPBACK;
+	else if (cpriv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+		mode = MCP25XXFD_CAN_CON_MODE_LISTENONLY;
+	else if (cpriv->can.ctrlmode & CAN_CTRLMODE_FD)
+		mode = MCP25XXFD_CAN_CON_MODE_MIXED;
+	else
+		mode = MCP25XXFD_CAN_CON_MODE_CAN2_0;
+
+	/* switch to active mode */
+	ret = mcp25xxfd_can_switch_mode(cpriv->priv, &cpriv->regs.con, mode);
+	if (ret)
+		goto out_int;
+
+	return 0;
+
+out_int:
+	mcp25xxfd_int_enable(cpriv->priv, false);
+out_canconfig:
+	mcp25xxfd_can_fifo_release(cpriv);
+out_power:
+	mcp25xxfd_base_power_enable(cpriv->transceiver, 0);
+out_irq:
+	free_irq(spi->irq, cpriv);
+	cpriv->irq.allocated = false;
+	cpriv->irq.enabled = false;
+out_candev:
+	close_candev(net);
+	return ret;
+}
+
+static void mcp25xxfd_can_shutdown(struct mcp25xxfd_can_priv *cpriv)
+{
+	/* switch us to CONFIG mode - this disables the controller */
+	mcp25xxfd_can_switch_mode(cpriv->priv, &cpriv->regs.con,
+				  MCP25XXFD_CAN_CON_MODE_CONFIG);
+}
+
+static int mcp25xxfd_can_stop(struct net_device *net)
+{
+	struct mcp25xxfd_can_priv *cpriv = netdev_priv(net);
+	struct mcp25xxfd_priv *priv = cpriv->priv;
+	struct spi_device *spi = priv->spi;
+
+	/* shutdown the can controller */
+	mcp25xxfd_can_shutdown(cpriv);
+
+	/* disable inerrupts on controller */
+	mcp25xxfd_int_enable(cpriv->priv, false);
+
+	/* disable the transceiver */
+	mcp25xxfd_base_power_enable(cpriv->transceiver, 0);
+
+	/* disable interrupt on host */
+	free_irq(spi->irq, cpriv);
+	cpriv->irq.allocated = false;
+	cpriv->irq.enabled = false;
+
+	/* close the can_decice */
+	close_candev(net);
+
+	return 0;
+}
+
+static const struct net_device_ops mcp25xxfd_netdev_ops = {
+	.ndo_open = mcp25xxfd_can_open,
+	.ndo_stop = mcp25xxfd_can_stop,
+	.ndo_change_mtu = can_change_mtu,
+};
+
+/* probe and remove */
+int mcp25xxfd_can_setup(struct mcp25xxfd_priv *priv)
+{
+	struct spi_device *spi = priv->spi;
+	struct mcp25xxfd_can_priv *cpriv;
+	struct net_device *net;
+	struct regulator *transceiver;
+	int ret;
+
+	/* get transceiver power regulator*/
+	transceiver = devm_regulator_get(&spi->dev, "xceiver");
+	if (PTR_ERR(transceiver) == -EPROBE_DEFER)
+		return PTR_ERR(transceiver);
+
+	/* allocate can device */
+	net = alloc_candev(sizeof(*cpriv), TX_ECHO_SKB_MAX);
+	if (!net)
+		return -ENOMEM;
+
+	cpriv = netdev_priv(net);
+	cpriv->priv = priv;
+	priv->cpriv = cpriv;
+
+	/* setup network */
+	SET_NETDEV_DEV(net, &spi->dev);
+	net->netdev_ops = &mcp25xxfd_netdev_ops;
+	net->flags |= IFF_ECHO;
+
+	cpriv->transceiver = transceiver;
+
+	cpriv->can.clock.freq = priv->clock_freq;
+	cpriv->can.bittiming_const =
+		&mcp25xxfd_can_nominal_bittiming_const;
+	cpriv->can.data_bittiming_const =
+		&mcp25xxfd_can_data_bittiming_const;
+
+	/* we are not setting bit-timing methods here as they get called by
+	 * the framework before open. So the controller would be still in sleep
+	 * mode, which does not help as things are configured in open instead.
+	 */
+	cpriv->can.do_set_mode =
+		mcp25xxfd_can_do_set_mode;
+	cpriv->can.do_get_berr_counter =
+		mcp25xxfd_can_get_berr_counter;
+	cpriv->can.ctrlmode_supported =
+		CAN_CTRLMODE_FD |
+		CAN_CTRLMODE_FD_NON_ISO |
+		CAN_CTRLMODE_LOOPBACK |
+		CAN_CTRLMODE_LISTENONLY |
+		CAN_CTRLMODE_BERR_REPORTING |
+		CAN_CTRLMODE_ONE_SHOT;
+
+	ret = register_candev(net);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to register can device\n");
+		goto out;
+	}
+
+	return 0;
+
+out:
+	free_candev(net);
+	priv->cpriv = NULL;
+
+	return ret;
+}
+
+void mcp25xxfd_can_remove(struct mcp25xxfd_priv *priv)
+{
+	if (priv->cpriv) {
+		unregister_candev(priv->cpriv->can.dev);
+		free_candev(priv->cpriv->can.dev);
+		priv->cpriv = NULL;
+	}
+}
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can.h b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can.h
index f54c716735fb..4b18b5bb3d45 100644
--- a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can.h
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can.h
@@ -8,9 +8,44 @@
 #ifndef __MCP25XXFD_CAN_H
 #define __MCP25XXFD_CAN_H
 
+#include "mcp25xxfd_can_priv.h"
 #include "mcp25xxfd_priv.h"
+#include "mcp25xxfd_regs.h"
+
+/* get the optimal controller target mode */
+static inline
+int mcp25xxfd_can_targetmode(struct mcp25xxfd_can_priv *cpriv)
+{
+	return (cpriv->can.dev->mtu == CAN_MTU) ?
+		MCP25XXFD_CAN_CON_MODE_CAN2_0 : MCP25XXFD_CAN_CON_MODE_MIXED;
+}
+
+static inline
+void mcp25xxfd_can_queue_frame(struct mcp25xxfd_can_priv *cpriv,
+			       s32 fifo, u16 ts)
+{
+	int idx = cpriv->fifos.submit_queue_count;
+
+	cpriv->fifos.submit_queue[idx].fifo = fifo;
+	cpriv->fifos.submit_queue[idx].ts = ts;
+
+	cpriv->fifos.submit_queue_count++;
+}
+
+/* get the current controller mode */
+int mcp25xxfd_can_get_mode(struct mcp25xxfd_priv *priv, u32 *reg);
+
+/* switch controller mode */
+int mcp25xxfd_can_switch_mode_no_wait(struct mcp25xxfd_priv *priv,
+				      u32 *reg, int mode);
+int mcp25xxfd_can_switch_mode(struct mcp25xxfd_priv *priv,
+			      u32 *reg, int mode);
 
 /* probe the can controller */
 int mcp25xxfd_can_probe(struct mcp25xxfd_priv *priv);
 
+/* setup and the can controller net interface */
+int mcp25xxfd_can_setup(struct mcp25xxfd_priv *priv);
+void mcp25xxfd_can_remove(struct mcp25xxfd_priv *priv);
+
 #endif /* __MCP25XXFD_CAN_H */
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_fifo.c b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_fifo.c
new file mode 100644
index 000000000000..4bd776772d2d
--- /dev/null
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_fifo.c
@@ -0,0 +1,228 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* CAN bus driver for Microchip 25XXFD CAN Controller with SPI Interface
+ *
+ * Copyright 2019 Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
+ */
+
+/* here we define and configure the fifo layout */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+
+#include "mcp25xxfd_can.h"
+#include "mcp25xxfd_can_fifo.h"
+#include "mcp25xxfd_can_priv.h"
+#include "mcp25xxfd_cmd.h"
+
+static int mcp25xxfd_can_fifo_get_address(struct mcp25xxfd_can_priv *cpriv)
+{
+	int fifo, ret;
+
+	/* we need to move out of config mode to force address computation */
+	ret = mcp25xxfd_can_switch_mode(cpriv->priv, &cpriv->regs.con,
+					MCP25XXFD_CAN_CON_MODE_INT_LOOPBACK);
+	if (ret)
+		return ret;
+
+	/* and get back into config mode */
+	ret = mcp25xxfd_can_switch_mode(cpriv->priv, &cpriv->regs.con,
+					MCP25XXFD_CAN_CON_MODE_CONFIG);
+	if (ret)
+		return ret;
+
+	/* read address and config back in */
+	for (fifo = 1; fifo < 32; fifo++) {
+		ret = mcp25xxfd_cmd_read(cpriv->priv->spi,
+					 MCP25XXFD_CAN_FIFOUA(fifo),
+					 &cpriv->fifos.info[fifo].offset);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int mcp25xxfd_can_fifo_setup_config(struct mcp25xxfd_can_priv *cpriv,
+					   struct mcp25xxfd_fifo *desc,
+					   u32 flags, u32 flags_last)
+{
+	u32 val;
+	int i, p, f, c, ret;
+
+	for (i = 0, f = desc->start, c = desc->count, p = 31;
+	     c > 0; i++, f++, p--, c--) {
+		val = (c > 1) ? flags : flags_last;
+
+		/* write the config to the controller in one go */
+		ret = mcp25xxfd_cmd_write(cpriv->priv->spi,
+					  MCP25XXFD_CAN_FIFOCON(f), val);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int mcp25xxfd_can_fifo_setup_rx(struct mcp25xxfd_can_priv *cpriv)
+{
+	u32 rx_flags = MCP25XXFD_CAN_FIFOCON_FRESET |     /* reset FIFO */
+		MCP25XXFD_CAN_FIFOCON_RXTSEN |            /* RX timestamps */
+		MCP25XXFD_CAN_FIFOCON_TFERFFIE |          /* FIFO Full */
+		MCP25XXFD_CAN_FIFOCON_TFHRFHIE |          /* FIFO Half Full*/
+		MCP25XXFD_CAN_FIFOCON_TFNRFNIE |          /* FIFO not empty */
+		(cpriv->fifos.payload_mode <<
+		 MCP25XXFD_CAN_FIFOCON_PLSIZE_SHIFT) |
+		(0 << MCP25XXFD_CAN_FIFOCON_FSIZE_SHIFT); /* 1 FIFO deep */
+	/* enable overflow int on last fifo */
+	u32 rx_flags_last = rx_flags | MCP25XXFD_CAN_FIFOCON_RXOVIE;
+
+	return mcp25xxfd_can_fifo_setup_config(cpriv, &cpriv->fifos.rx,
+					       rx_flags, rx_flags_last);
+}
+
+static int mcp25xxfd_can_fifo_setup_rxfilter(struct mcp25xxfd_can_priv *cpriv)
+{
+	u8 filter_con[32];
+	int c, f;
+
+	/* clear the filters and filter mappings for all filters */
+	memset(filter_con, 0, sizeof(filter_con));
+
+	/* and now set up the rx filters */
+	for (c = 0, f = cpriv->fifos.rx.start; c < cpriv->fifos.rx.count;
+	     c++, f++) {
+		/* set up filter config - we can use the mask of filter 0 */
+		filter_con[c] = MCP25XXFD_CAN_FIFOCON_FLTEN(0) |
+			(f << MCP25XXFD_CAN_FILCON_SHIFT(0));
+	}
+
+	/* and set up filter control */
+	return mcp25xxfd_cmd_write_regs(cpriv->priv->spi,
+					MCP25XXFD_CAN_FLTCON(0),
+					(u32 *)filter_con, sizeof(filter_con));
+}
+
+static int mcp25xxfd_can_fifo_compute(struct mcp25xxfd_can_priv *cpriv)
+{
+	int rx_memory_available;
+
+	switch (cpriv->can.dev->mtu) {
+	case CAN_MTU:
+		/* MTU is 8 */
+		cpriv->fifos.payload_size = 8;
+		cpriv->fifos.payload_mode = MCP25XXFD_CAN_TXQCON_PLSIZE_8;
+
+		break;
+	case CANFD_MTU:
+		/* MTU is 64 */
+		cpriv->fifos.payload_size = 64;
+		cpriv->fifos.payload_mode = MCP25XXFD_CAN_TXQCON_PLSIZE_64;
+
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* compute effective sizes */
+	cpriv->fifos.rx.size = sizeof(struct mcp25xxfd_can_obj_rx) +
+		cpriv->fifos.payload_size;
+
+	/* calculate evailable memory for RX_fifos */
+	rx_memory_available = MCP25XXFD_SRAM_SIZE;
+
+	/* calculate possible amount of RX fifos */
+	cpriv->fifos.rx.count = rx_memory_available / cpriv->fifos.rx.size;
+
+	/* now calculate effective number of rx-fifos. There are only 31 fifos
+	 * available in total, so we need to limit ourselves
+	 */
+	if (cpriv->fifos.rx.count > 31)
+		cpriv->fifos.rx.count = 31;
+
+	cpriv->fifos.rx.start = 1;
+
+	return 0;
+}
+
+static int mcp25xxfd_can_fifo_clear_regs(struct mcp25xxfd_can_priv *cpriv,
+					 u32 start, u32 end)
+{
+	size_t len = end - start;
+	u8 *data;
+	int ret;
+
+	data = kzalloc(len, GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	ret = mcp25xxfd_cmd_write_regs(cpriv->priv->spi,
+				       start, (u32 *)data, len);
+
+	kfree(data);
+
+	return ret;
+}
+
+static int mcp25xxfd_can_fifo_clear(struct mcp25xxfd_can_priv *cpriv)
+{
+	int ret;
+
+	memset(&cpriv->fifos.info, 0, sizeof(cpriv->fifos.info));
+	memset(&cpriv->fifos.rx, 0, sizeof(cpriv->fifos.rx));
+
+	/* clear FIFO config */
+	ret = mcp25xxfd_can_fifo_clear_regs(cpriv, MCP25XXFD_CAN_FIFOCON(1),
+					    MCP25XXFD_CAN_FIFOCON(32));
+	if (ret)
+		return ret;
+
+	/* clear the filter mask - match any frame with every filter */
+	return mcp25xxfd_can_fifo_clear_regs(cpriv, MCP25XXFD_CAN_FLTCON(0),
+					     MCP25XXFD_CAN_FLTCON(32));
+}
+
+int mcp25xxfd_can_fifo_setup(struct mcp25xxfd_can_priv *cpriv)
+{
+	int ret;
+
+	/* clear fifo config */
+	ret = mcp25xxfd_can_fifo_clear(cpriv);
+	if (ret)
+		return ret;
+
+	ret = mcp25xxfd_can_fifo_compute(cpriv);
+	if (ret)
+		return ret;
+
+	cpriv->regs.tefcon = 0;
+	ret = mcp25xxfd_cmd_write(cpriv->priv->spi, MCP25XXFD_CAN_TEFCON,
+				  cpriv->regs.tefcon);
+	if (ret)
+		return ret;
+
+	ret = mcp25xxfd_cmd_write(cpriv->priv->spi, MCP25XXFD_CAN_TXQCON, 0);
+	if (ret)
+		return ret;
+
+	ret = mcp25xxfd_can_fifo_setup_rx(cpriv);
+	if (ret)
+		return ret;
+
+	ret = mcp25xxfd_can_fifo_setup_rxfilter(cpriv);
+	if (ret)
+		return ret;
+
+	/* get fifo addresses */
+	ret = mcp25xxfd_can_fifo_get_address(cpriv);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+void mcp25xxfd_can_fifo_release(struct mcp25xxfd_can_priv *cpriv)
+{
+	mcp25xxfd_can_fifo_clear(cpriv);
+}
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_fifo.h b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_fifo.h
new file mode 100644
index 000000000000..ed2daa05220a
--- /dev/null
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_fifo.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* CAN bus driver for Microchip 25XXFD CAN Controller with SPI Interface
+ *
+ * Copyright 2019 Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
+ */
+
+#ifndef __MCP25XXFD_CAN_FIFO_H
+#define __MCP25XXFD_CAN_FIFO_H
+
+#include "mcp25xxfd_can_priv.h"
+
+int mcp25xxfd_can_fifo_setup(struct mcp25xxfd_can_priv *cpriv);
+void mcp25xxfd_can_fifo_release(struct mcp25xxfd_can_priv *cpriv);
+
+#endif /* __MCP25XXFD_CAN_FIFO_H */
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_id.h b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_id.h
new file mode 100644
index 000000000000..00a6c6639bd5
--- /dev/null
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_id.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* CAN bus driver for Microchip 25XXFD CAN Controller with SPI Interface
+ *
+ * Copyright 2019 Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
+ */
+
+#ifndef __MCP25XXFD_CAN_IF_H
+#define __MCP25XXFD_CAN_IF_H
+
+#include <uapi/linux/can.h>
+
+#include "mcp25xxfd_can_id.h"
+#include "mcp25xxfd_regs.h"
+
+/* ideally these would be defined in uapi/linux/can.h */
+#define MCP25XXFD_CAN_EFF_SID_SHIFT	(CAN_EFF_ID_BITS - CAN_SFF_ID_BITS)
+#define MCP25XXFD_CAN_EFF_SID_BITS	CAN_SFF_ID_BITS
+#define MCP25XXFD_CAN_EFF_SID_MASK					\
+	GENMASK(MCP25XXFD_CAN_EFF_SID_SHIFT + MCP25XXFD_CAN_EFF_SID_BITS - 1, \
+		MCP25XXFD_CAN_EFF_SID_SHIFT)
+#define MCP25XXFD_CAN_EFF_EID_SHIFT	0
+#define MCP25XXFD_CAN_EFF_EID_BITS	MCP25XXFD_CAN_EFF_SID_SHIFT
+#define MCP25XXFD_CAN_EFF_EID_MASK					\
+	GENMASK(MCP25XXFD_CAN_EFF_EID_SHIFT + MCP25XXFD_CAN_EFF_EID_BITS - 1, \
+		MCP25XXFD_CAN_EFF_EID_SHIFT)
+
+static inline
+void mcp25xxfd_can_id_from_mcp25xxfd(u32 mcp_id, u32 mcp_flags, u32 *can_id)
+{
+	u32 sid = (mcp_id & MCP25XXFD_CAN_OBJ_ID_SID_MASK) >>
+		MCP25XXFD_CAN_OBJ_ID_SID_SHIFT;
+	u32 eid = (mcp_id & MCP25XXFD_CAN_OBJ_ID_EID_MASK) >>
+		MCP25XXFD_CAN_OBJ_ID_EID_SHIFT;
+
+	/* select normal or extended ids */
+	if (mcp_flags & MCP25XXFD_CAN_OBJ_FLAGS_IDE) {
+		*can_id = (eid << MCP25XXFD_CAN_EFF_EID_SHIFT) |
+			(sid << MCP25XXFD_CAN_EFF_SID_SHIFT) |
+			CAN_EFF_FLAG;
+	} else {
+		*can_id = sid << MCP25XXFD_CAN_EFF_EID_SHIFT;
+	}
+	/* handle rtr */
+	*can_id |= (mcp_flags & MCP25XXFD_CAN_OBJ_FLAGS_RTR) ? CAN_RTR_FLAG : 0;
+}
+
+static inline
+void mcp25xxfd_can_id_to_mcp25xxfd(u32 can_id, u32 *id, u32 *flags)
+{
+	/* depending on can_id flag compute extended or standard ids */
+	if (can_id & CAN_EFF_FLAG) {
+		int sid = (can_id & MCP25XXFD_CAN_EFF_SID_MASK) >>
+			MCP25XXFD_CAN_EFF_SID_SHIFT;
+		int eid = (can_id & MCP25XXFD_CAN_EFF_EID_MASK) >>
+			MCP25XXFD_CAN_EFF_EID_SHIFT;
+		*id = (eid << MCP25XXFD_CAN_OBJ_ID_EID_SHIFT) |
+			(sid << MCP25XXFD_CAN_OBJ_ID_SID_SHIFT);
+		*flags = MCP25XXFD_CAN_OBJ_FLAGS_IDE;
+	} else {
+		*id = can_id & CAN_SFF_MASK;
+		*flags = 0;
+	}
+
+	/* Handle RTR */
+	*flags |= (can_id & CAN_RTR_FLAG) ? MCP25XXFD_CAN_OBJ_FLAGS_RTR : 0;
+}
+
+#endif /* __MCP25XXFD_CAN_IF_H */
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_int.c b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_int.c
new file mode 100644
index 000000000000..83656b2604df
--- /dev/null
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_int.c
@@ -0,0 +1,655 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* CAN bus driver for Microchip 25XXFD CAN Controller with SPI Interface
+ *
+ * Copyright 2019 Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
+ */
+
+#include <linux/can/core.h>
+#include <linux/can/dev.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+
+#include "mcp25xxfd_regs.h"
+#include "mcp25xxfd_can.h"
+#include "mcp25xxfd_can_int.h"
+#include "mcp25xxfd_can_priv.h"
+#include "mcp25xxfd_can_rx.h"
+#include "mcp25xxfd_cmd.h"
+#include "mcp25xxfd_ecc.h"
+
+#define MCP25XXFD_RESCHEDULE_TIMES 4
+
+static void mcp25xxfd_can_int_send_error_skb(struct mcp25xxfd_can_priv *cpriv)
+{
+	struct net_device *net = cpriv->can.dev;
+	struct sk_buff *skb;
+	struct can_frame *frame;
+
+	/* allocate error frame */
+	skb = alloc_can_err_skb(net, &frame);
+	if (!skb) {
+		netdev_err(net, "cannot allocate error skb\n");
+		return;
+	}
+
+	/* setup can error frame data */
+	frame->can_id |= cpriv->error_frame.id;
+	memcpy(frame->data, cpriv->error_frame.data, sizeof(frame->data));
+
+	/* and submit it */
+	netif_receive_skb(skb);
+}
+
+static int mcp25xxfd_can_int_compare_obj_ts(const void *a, const void *b)
+{
+	s32 ats = ((struct mcp25xxfd_obj_ts *)a)->ts;
+	s32 bts = ((struct mcp25xxfd_obj_ts *)b)->ts;
+
+	if (ats < bts)
+		return -1;
+	if (ats > bts)
+		return 1;
+
+	return 0;
+}
+
+static int mcp25xxfd_can_int_submit_frames(struct mcp25xxfd_can_priv *cpriv)
+{
+	struct mcp25xxfd_obj_ts *queue = cpriv->fifos.submit_queue;
+	int count = cpriv->fifos.submit_queue_count;
+	int i, fifo;
+	int ret;
+
+	/* skip processing if the queue count is 0 */
+	if (count == 0)
+		goto out;
+
+	/* sort the fifos (rx and tx - actually TEF) by receive timestamp */
+	sort(queue, count, sizeof(*queue),
+	     mcp25xxfd_can_int_compare_obj_ts, NULL);
+
+	/* now submit the fifos  */
+	for (i = 0; i < count; i++) {
+		fifo = queue[i].fifo;
+		ret = mcp25xxfd_can_rx_submit_frame(cpriv, fifo);
+		if (ret)
+			return ret;
+	}
+
+	/* if we have received or transmitted something and the IVMIE is
+	 * disabled, then enable it. This is mostly to avoid unnecessary
+	 * interrupts when CAN bus is disconnected.
+	 */
+	if (!(cpriv->status.intf | MCP25XXFD_CAN_INT_IVMIE)) {
+		cpriv->status.intf |= MCP25XXFD_CAN_INT_IVMIE;
+		ret = mcp25xxfd_cmd_write_mask(cpriv->priv->spi,
+					       MCP25XXFD_CAN_INT,
+					       cpriv->status.intf,
+					       MCP25XXFD_CAN_INT_IVMIE);
+		if (ret)
+			return ret;
+	}
+
+out:
+	return 0;
+}
+
+static int mcp25xxfd_can_int_clear_int_flags(struct mcp25xxfd_can_priv *cpriv)
+{
+	u32 clearable_irq_active = cpriv->status.intf &
+		MCP25XXFD_CAN_INT_IF_CLEAR_MASK;
+	u32 clear_irq = cpriv->status.intf & (~MCP25XXFD_CAN_INT_IF_CLEAR_MASK);
+
+	if (!clearable_irq_active)
+		return 0;
+
+	return mcp25xxfd_cmd_write_mask(cpriv->priv->spi, MCP25XXFD_CAN_INT,
+					clear_irq, clearable_irq_active);
+}
+
+static
+int mcp25xxfd_can_int_handle_serrif_txmab(struct mcp25xxfd_can_priv *cpriv)
+{
+	int mode = mcp25xxfd_can_targetmode(cpriv);
+
+	cpriv->can.dev->stats.tx_fifo_errors++;
+	cpriv->can.dev->stats.tx_errors++;
+
+	/* data7 contains custom mcp25xxfd error flags */
+	cpriv->error_frame.data[7] |= MCP25XXFD_CAN_ERR_DATA7_MCP25XXFD_SERR_TX;
+
+	/* and switch back into the correct mode */
+	return mcp25xxfd_can_switch_mode_no_wait(cpriv->priv,
+						 &cpriv->regs.con, mode);
+}
+
+static
+int mcp25xxfd_can_int_handle_serrif_rxmab(struct mcp25xxfd_can_priv *cpriv)
+{
+	cpriv->can.dev->stats.rx_dropped++;
+	cpriv->can.dev->stats.rx_errors++;
+
+	/* data7 contains custom mcp25xxfd error flags */
+	cpriv->error_frame.data[7] |= MCP25XXFD_CAN_ERR_DATA7_MCP25XXFD_SERR_RX;
+
+	return 0;
+}
+
+static int mcp25xxfd_can_int_handle_serrif(struct mcp25xxfd_can_priv *cpriv)
+{
+	if (!(cpriv->status.intf & MCP25XXFD_CAN_INT_SERRIF))
+		return 0;
+
+	/* Errors here are:
+	 * * Bus Bandwidth Error: when a RX Message Assembly Buffer
+	 *   is still full when the next message has already arrived
+	 *   the recived message shall be ignored
+	 * * TX MAB Underflow: when a TX Message is invalid
+	 *   due to ECC errors or TXMAB underflow
+	 *   in this situatioon the system will transition to
+	 *   Restricted or Listen Only mode
+	 */
+
+	cpriv->error_frame.id |= CAN_ERR_CRTL;
+	cpriv->error_frame.data[1] |= CAN_ERR_CRTL_UNSPEC;
+
+	/* mode change + invalid message would indicate TX MAB Underflow */
+	if ((cpriv->status.intf & MCP25XXFD_CAN_INT_MODIF) &&
+	    (cpriv->status.intf & MCP25XXFD_CAN_INT_IVMIF)) {
+		return mcp25xxfd_can_int_handle_serrif_txmab(cpriv);
+	}
+
+	/* for RX there is only the RXIF an indicator - surprizingly RX-MAB
+	 * does not change mode or anything
+	 */
+	if (cpriv->status.intf & MCP25XXFD_CAN_INT_RXIF)
+		return mcp25xxfd_can_int_handle_serrif_rxmab(cpriv);
+
+	dev_warn_ratelimited(&cpriv->priv->spi->dev,
+			     "unidentified system interrupt - intf =  %08x\n",
+			     cpriv->status.intf);
+
+	return 0;
+}
+
+static int mcp25xxfd_can_int_handle_modif(struct mcp25xxfd_can_priv *cpriv)
+{
+	struct spi_device *spi = cpriv->priv->spi;
+	int mode;
+	int ret;
+
+	/* Note that this irq does not get triggered in all situations
+	 * for example SERRIF will move to RESTICTED or LISTENONLY but MODIF
+	 * will not be raised!
+	 */
+	if (!(cpriv->status.intf & MCP25XXFD_CAN_INT_MODIF))
+		return 0;
+
+	/* get the current mode */
+	ret = mcp25xxfd_can_get_mode(cpriv->priv, &mode);
+	if (ret)
+		return ret;
+
+	mode = ret;
+
+	/* switches to the same mode as before are ignored
+	 * - this typically happens if the driver is shortly
+	 *   switching to a different mode and then returning to the
+	 *   original mode
+	 */
+	if (mode == cpriv->mode)
+		return 0;
+
+	/* if we are restricted, then return to "normal" mode */
+	if (mode == MCP25XXFD_CAN_CON_MODE_RESTRICTED) {
+		cpriv->mode = mode;
+		mode = mcp25xxfd_can_targetmode(cpriv);
+		return mcp25xxfd_can_switch_mode_no_wait(cpriv->priv,
+							 &cpriv->regs.con,
+							 mode);
+	}
+
+	/* the controller itself will transition to sleep, so we ignore it */
+	if (mode == MCP25XXFD_CAN_CON_MODE_SLEEP) {
+		cpriv->mode = mode;
+		return 0;
+	}
+
+	dev_warn(&spi->dev,
+		 "Controller unexpectedly switched from mode %u to %u\n",
+		 cpriv->mode, mode);
+
+	/* assign the mode as current */
+	cpriv->mode = mode;
+
+	return 0;
+}
+
+static int mcp25xxfd_can_int_handle_eccif(struct mcp25xxfd_can_priv *cpriv)
+{
+	if (!(cpriv->status.intf & MCP25XXFD_CAN_INT_ECCIF))
+		return 0;
+
+	/* and prepare ERROR FRAME */
+	cpriv->error_frame.id |= CAN_ERR_CRTL;
+	cpriv->error_frame.data[1] |= CAN_ERR_CRTL_UNSPEC;
+	/* data7 contains custom mcp25xxfd error flags */
+	cpriv->error_frame.data[7] |= MCP25XXFD_CAN_ERR_DATA7_MCP25XXFD_ECC;
+
+	/* delegate to interrupt cleaning */
+	return mcp25xxfd_ecc_clear_int(cpriv->priv);
+}
+
+static void mcp25xxfd_can_int_handle_ivmif_tx(struct mcp25xxfd_can_priv *cpriv,
+					      u32 *mask)
+{
+	/* check if it is really a known tx error */
+	if ((cpriv->bus.bdiag[1] &
+	     (MCP25XXFD_CAN_BDIAG1_DBIT1ERR |
+	      MCP25XXFD_CAN_BDIAG1_DBIT0ERR |
+	      MCP25XXFD_CAN_BDIAG1_NACKERR |
+	      MCP25XXFD_CAN_BDIAG1_NBIT1ERR |
+	      MCP25XXFD_CAN_BDIAG1_NBIT0ERR
+		     )) == 0)
+		return;
+
+	/* mark it as a protocol error */
+	cpriv->error_frame.id |= CAN_ERR_PROT;
+
+	/* and update statistics */
+	cpriv->can.dev->stats.tx_errors++;
+
+	/* and handle all the known cases */
+	if (cpriv->bus.bdiag[1] & MCP25XXFD_CAN_BDIAG1_NACKERR) {
+		/* TX-Frame not acknowledged - connected to CAN-bus? */
+		*mask |= MCP25XXFD_CAN_BDIAG1_NACKERR;
+		cpriv->error_frame.data[2] |= CAN_ERR_PROT_TX;
+		cpriv->can.dev->stats.tx_aborted_errors++;
+	}
+
+	if (cpriv->bus.bdiag[1] & MCP25XXFD_CAN_BDIAG1_NBIT1ERR) {
+		/* TX-Frame CAN-BUS Level is unexpectedly dominant */
+		*mask |= MCP25XXFD_CAN_BDIAG1_NBIT1ERR;
+		cpriv->can.dev->stats.tx_carrier_errors++;
+		cpriv->error_frame.data[2] |= CAN_ERR_PROT_BIT1;
+	}
+
+	if (cpriv->bus.bdiag[1] & MCP25XXFD_CAN_BDIAG1_NBIT0ERR) {
+		/* TX-Frame CAN-BUS Level is unexpectedly recessive */
+		*mask |= MCP25XXFD_CAN_BDIAG1_NBIT0ERR;
+		cpriv->can.dev->stats.tx_carrier_errors++;
+		cpriv->error_frame.data[2] |= CAN_ERR_PROT_BIT0;
+	}
+
+	if (cpriv->bus.bdiag[1] & MCP25XXFD_CAN_BDIAG1_DBIT1ERR) {
+		/* TX-Frame CAN-BUS Level is unexpectedly dominant
+		 * during data phase
+		 */
+		*mask |= MCP25XXFD_CAN_BDIAG1_DBIT1ERR;
+		cpriv->can.dev->stats.tx_carrier_errors++;
+		cpriv->error_frame.data[2] |= CAN_ERR_PROT_BIT1;
+	}
+
+	if (cpriv->bus.bdiag[1] & MCP25XXFD_CAN_BDIAG1_DBIT0ERR) {
+		/* TX-Frame CAN-BUS Level is unexpectedly recessive
+		 * during data phase
+		 */
+		*mask |= MCP25XXFD_CAN_BDIAG1_DBIT0ERR;
+		cpriv->can.dev->stats.tx_carrier_errors++;
+		cpriv->error_frame.data[2] |= CAN_ERR_PROT_BIT0;
+	}
+}
+
+static void mcp25xxfd_can_int_handle_ivmif_rx(struct mcp25xxfd_can_priv *cpriv,
+					      u32 *mask)
+{
+	/* check if it is really a known tx error */
+	if ((cpriv->bus.bdiag[1] &
+	     (MCP25XXFD_CAN_BDIAG1_DCRCERR |
+	      MCP25XXFD_CAN_BDIAG1_DSTUFERR |
+	      MCP25XXFD_CAN_BDIAG1_DFORMERR |
+	      MCP25XXFD_CAN_BDIAG1_NCRCERR |
+	      MCP25XXFD_CAN_BDIAG1_NSTUFERR |
+	      MCP25XXFD_CAN_BDIAG1_NFORMERR
+		     )) == 0)
+		return;
+
+	/* mark it as a protocol error */
+	cpriv->error_frame.id |= CAN_ERR_PROT;
+
+	/* and update statistics */
+	cpriv->can.dev->stats.rx_errors++;
+
+	/* handle the cases */
+	if (cpriv->bus.bdiag[1] & MCP25XXFD_CAN_BDIAG1_DCRCERR) {
+		/* RX-Frame with bad CRC during data phase */
+		*mask |= MCP25XXFD_CAN_BDIAG1_DCRCERR;
+		cpriv->can.dev->stats.rx_crc_errors++;
+		cpriv->error_frame.data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
+	}
+
+	if (cpriv->bus.bdiag[1] & MCP25XXFD_CAN_BDIAG1_DSTUFERR) {
+		/* RX-Frame with bad stuffing during data phase */
+		*mask |= MCP25XXFD_CAN_BDIAG1_DSTUFERR;
+		cpriv->can.dev->stats.rx_frame_errors++;
+		cpriv->error_frame.data[2] |= CAN_ERR_PROT_STUFF;
+	}
+
+	if (cpriv->bus.bdiag[1] & MCP25XXFD_CAN_BDIAG1_DFORMERR) {
+		/* RX-Frame with bad format during data phase */
+		*mask |= MCP25XXFD_CAN_BDIAG1_DFORMERR;
+		cpriv->can.dev->stats.rx_frame_errors++;
+		cpriv->error_frame.data[2] |= CAN_ERR_PROT_FORM;
+	}
+
+	if (cpriv->bus.bdiag[1] & MCP25XXFD_CAN_BDIAG1_NCRCERR) {
+		/* RX-Frame with bad CRC during data phase */
+		*mask |= MCP25XXFD_CAN_BDIAG1_NCRCERR;
+		cpriv->can.dev->stats.rx_crc_errors++;
+		cpriv->error_frame.data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
+	}
+
+	if (cpriv->bus.bdiag[1] & MCP25XXFD_CAN_BDIAG1_NSTUFERR) {
+		/* RX-Frame with bad stuffing during data phase */
+		*mask |= MCP25XXFD_CAN_BDIAG1_NSTUFERR;
+		cpriv->can.dev->stats.rx_frame_errors++;
+		cpriv->error_frame.data[2] |= CAN_ERR_PROT_STUFF;
+	}
+
+	if (cpriv->bus.bdiag[1] & MCP25XXFD_CAN_BDIAG1_NFORMERR) {
+		/* RX-Frame with bad format during data phase */
+		*mask |= MCP25XXFD_CAN_BDIAG1_NFORMERR;
+		cpriv->can.dev->stats.rx_frame_errors++;
+		cpriv->error_frame.data[2] |= CAN_ERR_PROT_FORM;
+	}
+}
+
+static int mcp25xxfd_can_int_handle_ivmif(struct mcp25xxfd_can_priv *cpriv)
+{
+	struct spi_device *spi = cpriv->priv->spi;
+	u32 mask, bdiag1;
+	int ret;
+
+	if (!(cpriv->status.intf & MCP25XXFD_CAN_INT_IVMIF))
+		return 0;
+
+	if (cpriv->status.intf & MCP25XXFD_CAN_INT_SERRIF)
+		return 0;
+
+	ret = mcp25xxfd_cmd_read_regs(spi, MCP25XXFD_CAN_BDIAG0,
+				      cpriv->bus.bdiag,
+				      sizeof(cpriv->bus.bdiag));
+	if (ret)
+		return ret;
+
+	mask = 0;
+
+	/* check rx and tx errors */
+	mcp25xxfd_can_int_handle_ivmif_tx(cpriv, &mask);
+	mcp25xxfd_can_int_handle_ivmif_rx(cpriv, &mask);
+
+	/* clear flags if we have bits masked */
+	if (!mask) {
+		dev_warn_once(&spi->dev,
+			      "found IVMIF situation not supported by driver - bdiag = [0x%08x, 0x%08x]",
+			      cpriv->bus.bdiag[0], cpriv->bus.bdiag[1]);
+		return -EINVAL;
+	}
+
+	bdiag1 = cpriv->bus.bdiag[1] & (~mask);
+	ret = mcp25xxfd_cmd_write_mask(spi, MCP25XXFD_CAN_BDIAG1, bdiag1, mask);
+	if (ret)
+		return ret;
+
+	/* clear the interrupt flag until we have received or transmited */
+	cpriv->status.intf &= ~(MCP25XXFD_CAN_INT_IVMIE);
+	return mcp25xxfd_cmd_write_mask(spi, MCP25XXFD_CAN_INT,
+					cpriv->status.intf,
+					MCP25XXFD_CAN_INT_IVMIE);
+}
+
+static int mcp25xxfd_can_int_handle_cerrif(struct mcp25xxfd_can_priv *cpriv)
+{
+	if (!(cpriv->status.intf & MCP25XXFD_CAN_INT_CERRIF))
+		return 0;
+
+	/* this interrupt exists primarilly to counter possible bus off
+	 * situations. More detailed information can be found and controlled in
+	 * the TREC register
+	 */
+
+	netdev_warn(cpriv->can.dev, "CAN Bus error experienced");
+
+	return 0;
+}
+
+static int mcp25xxfd_can_int_error_counters(struct mcp25xxfd_can_priv *cpriv)
+{
+	if (cpriv->status.trec & MCP25XXFD_CAN_TREC_TXWARN) {
+		cpriv->bus.new_state = CAN_STATE_ERROR_WARNING;
+		cpriv->error_frame.id |= CAN_ERR_CRTL;
+		cpriv->error_frame.data[1] |= CAN_ERR_CRTL_TX_WARNING;
+	}
+
+	if (cpriv->status.trec & MCP25XXFD_CAN_TREC_RXWARN) {
+		cpriv->bus.new_state = CAN_STATE_ERROR_WARNING;
+		cpriv->error_frame.id |= CAN_ERR_CRTL;
+		cpriv->error_frame.data[1] |= CAN_ERR_CRTL_RX_WARNING;
+	}
+
+	if (cpriv->status.trec & MCP25XXFD_CAN_TREC_TXBP) {
+		cpriv->bus.new_state = CAN_STATE_ERROR_PASSIVE;
+		cpriv->error_frame.id |= CAN_ERR_CRTL;
+		cpriv->error_frame.data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
+	}
+
+	if (cpriv->status.trec & MCP25XXFD_CAN_TREC_RXBP) {
+		cpriv->bus.new_state = CAN_STATE_ERROR_PASSIVE;
+		cpriv->error_frame.id |= CAN_ERR_CRTL;
+		cpriv->error_frame.data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
+	}
+
+	if (cpriv->status.trec & MCP25XXFD_CAN_TREC_TXBO) {
+		cpriv->bus.new_state = CAN_STATE_BUS_OFF;
+		cpriv->error_frame.id |= CAN_ERR_BUSOFF;
+	}
+
+	return 0;
+}
+
+static int mcp25xxfd_can_int_error_handling(struct mcp25xxfd_can_priv *cpriv)
+{
+	/* based on the last state state check the new state */
+	switch (cpriv->can.state) {
+	case CAN_STATE_ERROR_ACTIVE:
+		if (cpriv->bus.new_state >= CAN_STATE_ERROR_WARNING &&
+		    cpriv->bus.new_state <= CAN_STATE_BUS_OFF)
+			cpriv->can.can_stats.error_warning++;
+		fallthrough;
+	case CAN_STATE_ERROR_WARNING:
+		if (cpriv->bus.new_state >= CAN_STATE_ERROR_PASSIVE &&
+		    cpriv->bus.new_state <= CAN_STATE_BUS_OFF)
+			cpriv->can.can_stats.error_passive++;
+		break;
+	default:
+		break;
+	}
+
+	cpriv->can.state = cpriv->bus.new_state;
+
+	/* send error packet */
+	if (cpriv->error_frame.id)
+		mcp25xxfd_can_int_send_error_skb(cpriv);
+
+	/* handle BUS OFF */
+	if (cpriv->can.state == CAN_STATE_BUS_OFF) {
+		if (cpriv->can.restart_ms == 0) {
+			cpriv->can.can_stats.bus_off++;
+			can_bus_off(cpriv->can.dev);
+		}
+	}
+
+	return 0;
+}
+
+static int mcp25xxfd_can_int_handle_status(struct mcp25xxfd_can_priv *cpriv)
+{
+	int ret;
+
+	ret = mcp25xxfd_can_int_clear_int_flags(cpriv);
+	if (ret)
+		return ret;
+
+	/* set up new state and error frame for this loop */
+	cpriv->bus.new_state = cpriv->bus.state;
+	memset(&cpriv->error_frame, 0, sizeof(cpriv->error_frame));
+
+	/* setup the process queue by clearing the counter */
+	cpriv->fifos.submit_queue_count = 0;
+
+	/* system error interrupt needs to get handled first
+	 * to get us out of restricted mode
+	 */
+	ret = mcp25xxfd_can_int_handle_serrif(cpriv);
+	if (ret)
+		return ret;
+
+	/* mode change interrupt */
+	ret = mcp25xxfd_can_int_handle_modif(cpriv);
+	if (ret)
+		return ret;
+
+	/* handle the rx */
+	ret = mcp25xxfd_can_rx_handle_int_rxif(cpriv);
+	if (ret)
+		return ret;
+
+	/* handle error interrupt flags */
+	ret = mcp25xxfd_can_rx_handle_int_rxovif(cpriv);
+	if (ret)
+		return ret;
+
+	/* sram ECC error interrupt */
+	ret = mcp25xxfd_can_int_handle_eccif(cpriv);
+	if (ret)
+		return ret;
+
+	/* message format interrupt */
+	ret = mcp25xxfd_can_int_handle_ivmif(cpriv);
+	if (ret)
+		return ret;
+
+	/* handle bus errors in more detail */
+	ret = mcp25xxfd_can_int_handle_cerrif(cpriv);
+	if (ret)
+		return ret;
+
+	/* error counter handling */
+	ret = mcp25xxfd_can_int_error_counters(cpriv);
+	if (ret)
+		return ret;
+
+	/* error counter handling */
+	ret = mcp25xxfd_can_int_error_handling(cpriv);
+	if (ret)
+		return ret;
+
+	/* and submit can frames to network stack */
+	ret = mcp25xxfd_can_int_submit_frames(cpriv);
+
+	return ret;
+}
+
+irqreturn_t mcp25xxfd_can_int(int irq, void *dev_id)
+{
+	struct mcp25xxfd_can_priv *cpriv = dev_id;
+	int loops, ret;
+
+	/* loop forever unless we need to exit */
+	for (loops = 0; true; loops++) {
+		/* read interrupt status flags in bulk */
+		ret = mcp25xxfd_cmd_read_regs(cpriv->priv->spi,
+					      MCP25XXFD_CAN_INT,
+					      &cpriv->status.intf,
+					      sizeof(cpriv->status));
+		if (ret)
+			return ret;
+
+		/* only act if the IE mask configured has active IF bits
+		 * otherwise the Interrupt line should be deasserted already
+		 * so we can exit the loop
+		 */
+		if (((cpriv->status.intf >> MCP25XXFD_CAN_INT_IE_SHIFT) &
+		       cpriv->status.intf) == 0)
+			break;
+
+		/* handle the status */
+		ret = mcp25xxfd_can_int_handle_status(cpriv);
+		if (ret)
+			return ret;
+
+		/* allow voluntarily rescheduling every so often to avoid
+		 * long CS lows at the end of a transfer on low power CPUs
+		 * avoiding SERR happening
+		 */
+		if (loops % MCP25XXFD_RESCHEDULE_TIMES == 0)
+			cond_resched();
+	}
+
+	return IRQ_HANDLED;
+}
+
+int mcp25xxfd_can_int_clear(struct mcp25xxfd_priv *priv)
+{
+	return mcp25xxfd_cmd_write_mask(priv->spi, MCP25XXFD_CAN_INT, 0,
+					MCP25XXFD_CAN_INT_IF_MASK);
+}
+
+int mcp25xxfd_can_int_enable(struct mcp25xxfd_priv *priv, bool enable)
+{
+	struct mcp25xxfd_can_priv *cpriv = priv->cpriv;
+	const u32 mask = MCP25XXFD_CAN_INT_TEFIE |
+		MCP25XXFD_CAN_INT_RXIE |
+		MCP25XXFD_CAN_INT_MODIE |
+		MCP25XXFD_CAN_INT_SERRIE |
+		MCP25XXFD_CAN_INT_IVMIE |
+		MCP25XXFD_CAN_INT_CERRIE |
+		MCP25XXFD_CAN_INT_RXOVIE |
+		MCP25XXFD_CAN_INT_ECCIE;
+	u32 value = cpriv ? cpriv->status.intf : 0;
+	int ret;
+
+	value &= ~(MCP25XXFD_CAN_INT_IE_MASK);
+	if (enable)
+		value |= mask;
+
+	ret = mcp25xxfd_cmd_write_mask(priv->spi, MCP25XXFD_CAN_INT,
+				       value, mask);
+	if (ret)
+		return ret;
+
+	if (!cpriv)
+		return 0;
+
+	cpriv->status.intf = value;
+	if (cpriv->irq.allocated) {
+		if (enable && !cpriv->irq.enabled)
+			enable_irq(cpriv->priv->spi->irq);
+		if (!enable && cpriv->irq.enabled)
+			disable_irq(cpriv->priv->spi->irq);
+		cpriv->irq.enabled = enable;
+	} else {
+		cpriv->irq.enabled = false;
+	}
+
+	return 0;
+}
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_int.h b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_int.h
new file mode 100644
index 000000000000..aa67a5da9271
--- /dev/null
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_int.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* CAN bus driver for Microchip 25XXFD CAN Controller with SPI Interface
+ *
+ * Copyright 2019 Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
+ */
+#ifndef __MCP25XXFD_CAN_INT_H
+#define __MCP25XXFD_CAN_INT_H
+
+#include "mcp25xxfd_priv.h"
+#include <linux/irqreturn.h>
+
+int mcp25xxfd_can_int_clear(struct mcp25xxfd_priv *priv);
+int mcp25xxfd_can_int_enable(struct mcp25xxfd_priv *priv, bool enable);
+
+irqreturn_t mcp25xxfd_can_int(int irq, void *dev_id);
+
+#endif /* __MCP25XXFD_CAN_INT_H */
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_priv.h b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_priv.h
new file mode 100644
index 000000000000..e043b262a868
--- /dev/null
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_priv.h
@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* CAN bus driver for Microchip 25XXFD CAN Controller with SPI Interface
+ *
+ * Copyright 2019 Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
+ */
+
+#ifndef __MCP25XXFD_CAN_PRIV_H
+#define __MCP25XXFD_CAN_PRIV_H
+
+#include <linux/can/dev.h>
+#include <linux/dcache.h>
+
+#include "mcp25xxfd_priv.h"
+
+#define TX_ECHO_SKB_MAX	32
+
+/* information on each fifo type */
+struct mcp25xxfd_fifo {
+	u32 count;
+	u32 start;
+	u32 size;
+};
+
+/* used for sorting incoming messages */
+struct mcp25xxfd_obj_ts {
+	s32 ts; /* using signed to handle rollover correctly when sorting */
+	u16 fifo;
+};
+
+/* general info on each fifo */
+struct mcp25xxfd_fifo_info {
+	u32 offset;
+	u32 priority;
+};
+
+struct mcp25xxfd_can_priv {
+	/* can_priv has to be the first one to be usable with alloc_candev
+	 * which expects struct can_priv to be right at the start of the
+	 * priv structure
+	 */
+	struct can_priv can;
+	struct mcp25xxfd_priv *priv;
+	struct regulator *transceiver;
+
+	/* the can mode currently active */
+	int mode;
+
+	/* interrupt state */
+	struct {
+		int enabled;
+		int allocated;
+	} irq;
+
+	/* can config registers */
+	struct {
+		u32 con;
+		u32 tdc;
+		u32 tscon;
+		u32 tefcon;
+		u32 nbtcfg;
+		u32 dbtcfg;
+	} regs;
+
+	/* can status registers (mostly) - read in one go
+	 * bdiag0 and bdiag1 are optional, but when
+	 * berr counters are requested on a regular basis
+	 * during high CAN-bus load this would trigger the fact
+	 * that spi_sync would get queued for execution in the
+	 * spi thread and the spi handler would not get
+	 * called inline in the interrupt thread without any
+	 * context switches or wakeups...
+	 */
+	struct {
+		u32 intf;
+		/* ASSERT(CAN_INT + 4 == CAN_RXIF) */
+		u32 rxif;
+		/* ASSERT(CAN_RXIF + 4 == CAN_TXIF) */
+		u32 txif;
+		/* ASSERT(CAN_TXIF + 4 == CAN_RXOVIF) */
+		u32 rxovif;
+		/* ASSERT(CAN_RXOVIF + 4 == CAN_TXATIF) */
+		u32 txatif;
+		/* ASSERT(CAN_TXATIF + 4 == CAN_TXREQ) */
+		u32 txreq;
+		/* ASSERT(CAN_TXREQ + 4 == CAN_TREC) */
+		u32 trec;
+	} status;
+
+	/* information of fifo setup */
+	struct {
+		/* define payload size and mode */
+		u32 payload_size;
+		u32 payload_mode;
+
+		/* infos on fifo layout */
+
+		/* info on each fifo */
+		struct mcp25xxfd_fifo_info info[32];
+
+		/* extra info on rx fifo groups */
+		struct mcp25xxfd_fifo rx;
+
+		/* queue of can frames that need to get submitted
+		 * to the network stack during an interrupt loop in one go
+		 * (this gets sorted by timestamp before submission
+		 * and contains both rx frames as well tx frames that have
+		 * gone over the CAN bus successfully
+		 */
+		struct mcp25xxfd_obj_ts submit_queue[32];
+		int  submit_queue_count;
+	} fifos;
+
+	/* bus state */
+	struct {
+		u32 state;
+		u32 new_state;
+		u32 bdiag[2];
+	} bus;
+
+	/* can error messages */
+	struct {
+		u32 id;
+		u8  data[8];
+	} error_frame;
+
+	/* a copy of mcp25xxfd-sram in ram */
+	u8 sram[MCP25XXFD_SRAM_SIZE];
+};
+
+#endif /* __MCP25XXFD_CAN_PRIV_H */
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_rx.c b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_rx.c
new file mode 100644
index 000000000000..5e3f706e7a3f
--- /dev/null
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_rx.c
@@ -0,0 +1,233 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* CAN bus driver for Microchip 25XXFD CAN Controller with SPI Interface
+ *
+ * Copyright 2019 Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
+ *
+ * Based on Microchip MCP251x CAN controller driver written by
+ * David Vrabel, Copyright 2006 Arcom Control Systems Ltd.
+ */
+
+#include <linux/can/core.h>
+#include <linux/can/dev.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+
+#include "mcp25xxfd_cmd.h"
+#include "mcp25xxfd_can.h"
+#include "mcp25xxfd_can_id.h"
+#include "mcp25xxfd_can_priv.h"
+#include "mcp25xxfd_can_rx.h"
+
+static struct sk_buff *
+mcp25xxfd_can_rx_submit_normal_frame(struct mcp25xxfd_can_priv *cpriv,
+				     u32 id, u32 dlc, u8 **data)
+{
+	struct can_frame *frame;
+	struct sk_buff *skb;
+
+	/* allocate frame */
+	skb = alloc_can_skb(cpriv->can.dev, &frame);
+	if (!skb)
+		return NULL;
+
+	/* set id, dlc and flags */
+	frame->can_id = id;
+	frame->can_dlc = dlc;
+
+	/* and set the pointer to data */
+	*data = frame->data;
+
+	return skb;
+}
+
+/* it is almost identical except for the type of the frame... */
+static struct sk_buff *
+mcp25xxfd_can_rx_submit_fd_frame(struct mcp25xxfd_can_priv *cpriv,
+				 u32 id, u32 flags, u32 len, u8 **data)
+{
+	struct canfd_frame *frame;
+	struct sk_buff *skb;
+
+	/* allocate frame */
+	skb = alloc_canfd_skb(cpriv->can.dev, &frame);
+	if (!skb)
+		return NULL;
+
+	/* set id, dlc and flags */
+	frame->can_id = id;
+	frame->len = len;
+	frame->flags |= flags;
+
+	/* and set the pointer to data */
+	*data = frame->data;
+
+	return skb;
+}
+
+int mcp25xxfd_can_rx_submit_frame(struct mcp25xxfd_can_priv *cpriv, int fifo)
+{
+	struct net_device *net = cpriv->can.dev;
+	int addr = cpriv->fifos.info[fifo].offset;
+	struct mcp25xxfd_can_obj_rx *rx =
+		(struct mcp25xxfd_can_obj_rx *)(cpriv->sram + addr);
+	u8 *data = NULL;
+	struct sk_buff *skb;
+	u32 id, dlc, len, flags;
+
+	/* compute the can_id */
+	mcp25xxfd_can_id_from_mcp25xxfd(rx->id, rx->flags, &id);
+
+	/* and dlc */
+	dlc = (rx->flags & MCP25XXFD_CAN_OBJ_FLAGS_DLC_MASK) >>
+		MCP25XXFD_CAN_OBJ_FLAGS_DLC_SHIFT;
+	len = can_dlc2len(dlc);
+
+	/* update stats */
+	net->stats.rx_packets++;
+	net->stats.rx_bytes += len;
+
+	/* allocate the skb buffer */
+	if (rx->flags & MCP25XXFD_CAN_OBJ_FLAGS_FDF) {
+		flags = 0;
+		flags |= (rx->flags & MCP25XXFD_CAN_OBJ_FLAGS_BRS) ?
+			CANFD_BRS : 0;
+		flags |= (rx->flags & MCP25XXFD_CAN_OBJ_FLAGS_ESI) ?
+			CANFD_ESI : 0;
+		skb = mcp25xxfd_can_rx_submit_fd_frame(cpriv, id, flags,
+						       len, &data);
+	} else {
+		skb = mcp25xxfd_can_rx_submit_normal_frame(cpriv, id,
+							   len, &data);
+	}
+	if (!skb) {
+		netdev_err(net, "cannot allocate RX skb\n");
+		net->stats.rx_dropped++;
+		return -ENOMEM;
+	}
+
+	/* copy the payload data */
+	memcpy(data, rx->data, len);
+
+	/* and submit the frame */
+	netif_rx_ni(skb);
+
+	return 0;
+}
+
+static int mcp25xxfd_can_rx_read_frame(struct mcp25xxfd_can_priv *cpriv,
+				       int fifo, int prefetch_bytes)
+{
+	struct spi_device *spi = cpriv->priv->spi;
+	struct net_device *net = cpriv->can.dev;
+	int addr = cpriv->fifos.info[fifo].offset;
+	struct mcp25xxfd_can_obj_rx *rx =
+		(struct mcp25xxfd_can_obj_rx *)(cpriv->sram + addr);
+	int dlc;
+	int len, ret;
+
+	/* we read the header plus prefetch_bytes */
+	ret = mcp25xxfd_cmd_read_multi(spi, MCP25XXFD_SRAM_ADDR(addr),
+				       rx, sizeof(*rx) + prefetch_bytes);
+	if (ret)
+		return ret;
+
+	/* transpose the headers to CPU format*/
+	rx->id = le32_to_cpu(rx->id);
+	rx->flags = le32_to_cpu(rx->flags);
+	rx->ts = le32_to_cpu(rx->ts);
+
+	/* compute len */
+	dlc = (rx->flags & MCP25XXFD_CAN_OBJ_FLAGS_DLC_MASK) >>
+		MCP25XXFD_CAN_OBJ_FLAGS_DLC_SHIFT;
+	len = can_dlc2len(min_t(int, dlc, (net->mtu == CANFD_MTU) ? 15 : 8));
+
+	/* read the remaining data for canfd frames */
+	if (len > prefetch_bytes) {
+		/* here the extra portion reading data after prefetch */
+		ret = mcp25xxfd_cmd_read_multi(spi,
+					       MCP25XXFD_SRAM_ADDR(addr) +
+					       sizeof(*rx) + prefetch_bytes,
+					       &rx->data[prefetch_bytes],
+					       len - prefetch_bytes);
+		if (ret)
+			return ret;
+	}
+
+	/* clear the rest of the buffer - just to be safe */
+	memset(rx->data + len, 0, ((net->mtu == CANFD_MTU) ? 64 : 8) - len);
+
+	/* add the fifo to the process queues */
+	mcp25xxfd_can_queue_frame(cpriv, fifo, rx->ts);
+
+	/* and clear the interrupt flag for that fifo */
+	return mcp25xxfd_cmd_write_mask(spi, MCP25XXFD_CAN_FIFOCON(fifo),
+					MCP25XXFD_CAN_FIFOCON_FRESET,
+					MCP25XXFD_CAN_FIFOCON_FRESET);
+}
+
+static int mcp25xxfd_can_rx_read_frames(struct mcp25xxfd_can_priv *cpriv)
+{
+	int i, f, prefetch;
+	int ret;
+
+	prefetch = 8;
+	/* TODO: Optimize this */
+	for (i = 0, f = cpriv->fifos.rx.start; i < cpriv->fifos.rx.count;
+	     i++, f++) {
+		if (cpriv->status.rxif & BIT(f)) {
+			/* read the frame */
+			ret = mcp25xxfd_can_rx_read_frame(cpriv, f, prefetch);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+int mcp25xxfd_can_rx_handle_int_rxif(struct mcp25xxfd_can_priv *cpriv)
+{
+	if (!cpriv->status.rxif)
+		return 0;
+
+	/* read all the fifos */
+	return mcp25xxfd_can_rx_read_frames(cpriv);
+}
+
+int mcp25xxfd_can_rx_handle_int_rxovif(struct mcp25xxfd_can_priv *cpriv)
+{
+	u32 mask = MCP25XXFD_CAN_FIFOSTA_RXOVIF;
+	int ret, i, reg;
+
+	if (!cpriv->status.rxovif)
+		return 0;
+
+	/* clear all fifos that have an overflow bit set */
+	for (i = 0; i < 32; i++) {
+		if (cpriv->status.rxovif & BIT(i)) {
+			/* clear fifo status */
+			reg = MCP25XXFD_CAN_FIFOSTA(i);
+			ret = mcp25xxfd_cmd_write_mask(cpriv->priv->spi,
+						       reg, 0, mask);
+			if (ret)
+				return ret;
+
+			/* update statistics */
+			cpriv->can.dev->stats.rx_over_errors++;
+			cpriv->can.dev->stats.rx_errors++;
+
+			/* and prepare ERROR FRAME */
+			cpriv->error_frame.id |= CAN_ERR_CRTL;
+			cpriv->error_frame.data[1] |=
+				CAN_ERR_CRTL_RX_OVERFLOW;
+		}
+	}
+
+	return 0;
+}
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_rx.h b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_rx.h
new file mode 100644
index 000000000000..71953e2f3615
--- /dev/null
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_can_rx.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* CAN bus driver for Microchip 25XXFD CAN Controller with SPI Interface
+ *
+ * Copyright 2019 Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
+ */
+
+#ifndef __MCP25XXFD_CAN_RX_H
+#define __MCP25XXFD_CAN_RX_H
+
+#include "mcp25xxfd_priv.h"
+
+int mcp25xxfd_can_rx_submit_frame(struct mcp25xxfd_can_priv *cpriv, int fifo);
+
+int mcp25xxfd_can_rx_handle_int_rxif(struct mcp25xxfd_can_priv *cpriv);
+int mcp25xxfd_can_rx_handle_int_rxovif(struct mcp25xxfd_can_priv *cpriv);
+
+#endif /* __MCP25XXFD_CAN_RX_H */
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_int.c b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_int.c
index 5e274d452646..182172b6c59c 100644
--- a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_int.c
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_int.c
@@ -8,6 +8,7 @@
 #include <linux/kernel.h>
 #include <linux/spi/spi.h>
 
+#include "mcp25xxfd_can_int.h"
 #include "mcp25xxfd_crc.h"
 #include "mcp25xxfd_ecc.h"
 #include "mcp25xxfd_int.h"
@@ -21,7 +22,11 @@ int mcp25xxfd_int_clear(struct mcp25xxfd_priv *priv)
 	if (ret)
 		return ret;
 
-	return mcp25xxfd_crc_clear_int(priv);
+	ret = mcp25xxfd_crc_clear_int(priv);
+	if (ret)
+		return ret;
+
+	return mcp25xxfd_can_int_clear(priv);
 }
 
 int mcp25xxfd_int_enable(struct mcp25xxfd_priv *priv, bool enable)
@@ -47,12 +52,19 @@ int mcp25xxfd_int_enable(struct mcp25xxfd_priv *priv, bool enable)
 	if (ret)
 		goto out_crc;
 
+	ret = mcp25xxfd_can_int_enable(priv, enable);
+	if (ret)
+		goto out_ecc;
+
 	/* If we disable interrupts, then clear interrupt flags last */
 	if (!enable)
 		mcp25xxfd_int_clear(priv);
 
 	return 0;
 
+out_ecc:
+	mcp25xxfd_ecc_enable_int(priv, false);
+
 out_crc:
 	mcp25xxfd_crc_enable_int(priv, false);
 	return ret;
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_priv.h b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_priv.h
index 8bc7a599224c..85c27a7f6785 100644
--- a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_priv.h
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_priv.h
@@ -23,9 +23,11 @@ enum mcp25xxfd_model {
 	CAN_MCP2517FD	= 0x2517,
 };
 
+struct mcp25xxfd_can_priv;
 struct mcp25xxfd_priv {
 	struct spi_device *spi;
 	struct clk *clk;
+	struct mcp25xxfd_can_priv *cpriv;
 
 	/* actual model of the mcp25xxfd */
 	enum mcp25xxfd_model model;
diff --git a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_regs.h b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_regs.h
index b500cb46b9a4..222527439c70 100644
--- a/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_regs.h
+++ b/drivers/net/can/spi/mcp25xxfd/mcp25xxfd_regs.h
@@ -653,4 +653,9 @@ struct mcp25xxfd_can_obj_tef {
 		MCP25XXFD_CAN_FLAGS_FILHIT_BITS - 1,			\
 		MCP25XXFD_CAN_FLAGS_FILHIT_SHIFT)
 
+/* custom status error */
+#define MCP25XXFD_CAN_ERR_DATA7_MCP25XXFD_SERR_RX BIT(0)
+#define MCP25XXFD_CAN_ERR_DATA7_MCP25XXFD_SERR_TX BIT(1)
+#define MCP25XXFD_CAN_ERR_DATA7_MCP25XXFD_ECC	  BIT(2)
+
 #endif /* __MCP25XXFD_REGS_H */
-- 
2.17.1